帮我用C#写一个modbusRtuOverTCP 服务器

当然可以！以下是一个使用C#编写的Modbus RTU over TCP服务器的示例代码：

using System;
using System.IO.Ports;
using System.Net;
using System.Net.Sockets;

namespace ModbusServer
{
    class Program
    {
        static void Main(string[] args)
        {
            // 设置Modbus服务器的IP地址和端口号
            IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
            int port = 502;

            // 创建TCP监听器
            TcpListener listener = new TcpListener(ipAddress, port);
            listener.Start();
            Console.WriteLine("Modbus server started.");

            while (true)
            {
                // 接受客户端连接
                TcpClient client = listener.AcceptTcpClient();
                Console.WriteLine("Client connected.");

                // 处理客户端请求
                HandleClient(client);
            }
        }

        static void HandleClient(TcpClient client)
        {
            // 设置Modbus串口参数
            SerialPort serialPort = new SerialPort("COM1", 9600, Parity.None, 8, StopBits.One);

            // 打开Modbus串口
            serialPort.Open();
            Console.WriteLine("Serial port opened.");

            // 获取网络流和串口流
            NetworkStream networkStream = client.GetStream();
            SerialPortStream serialPortStream = new SerialPortStream(serialPort);

            while (true)
            {
                try
                {
                    // 从网络流中读取Modbus请求
                    byte[] request = new byte[256];
                    int bytesRead = networkStream.Read(request, 0, request.Length);

                    // 将Modbus请求发送到串口
                    serialPortStream.Write(request, 0, bytesRead);

                    // 从串口读取Modbus响应
                    byte[] response = new byte[256];
                    int bytesWritten = serialPortStream.Read(response, 0, response.Length);

                    // 将Modbus响应发送回客户端
                    networkStream.Write(response, 0, bytesWritten);
                }
                catch (Exception ex)
                {
                    Console.WriteLine("Error: " + ex.Message);
                    break;
                }
            }

            // 关闭网络流和串口
            networkStream.Close();
            serialPortStream.Close();
            client.Close();
            Console.WriteLine("Client disconnected.");
        }
    }
}

请注意，此代码仅为示例，需要根据实际情况进行修改和完善。